Lift mechanism



Now-11 1969 A. DAYSON LIFT MECHANISM 4 Sheets-Sheet 1 Filed Jan. 2, 1968 FIG..IY

' INVENTOR.

M %S Y S {E M N. R D 0 W R U A H I T R A m Y B Nov. 11, 1969 A, DAYSON 3,477,343

' LIFT MECHANISM Eild Jan, 2. 1968 4 Sheets-Sheet 2.

v 44 L ns INVENTOR.

ARTHUR DAYSON 'BY ATTOR N EYS A. DAYSON LIFT MECHANISM Nov. 11, 1969 Filed Jan. 2, 19

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Nov. 11, 19 9 A. DAYSON LIFT MECHANISM Filed Jan. 2. 1968 4 Sheets-Sheet 4 INVENTOR.

ARTHUR DAYSON BY ATTORNEYS United States Patent US. Cl. 914 20 Claims ABSTRACT OF THE DISCLOSURE A lift for moving a load, such as a vehicle from ground level upwardly and returning the load to ground level comprising a reciprocal fluid powered cylinder and piston unit and including an air valve assembly for controlling the application of air pressure to the operating liquid for the vehicle lift, which liquid is adapted when under predetermined air pressure to cause raising of the piston of the lift with respect to the cylinder. The valve assembly includes an axially movable valve with a depending stern, a float movable relative to the stem and operable to move the valve upwardly into closed position against a valve seat, and shoulder means on the stem for locking the valve in closed condition during separation of the float and the liquid upon raising of the lift. The valve mechanism includes adjustable lock seat means for coaction with the aforementioned shoulder means on the stem, as actuated by the float, for locking the valve in closed condition as the operating liquid and float separate during application of air pressure in the raising operation of the lift, so that even though the level of the liquid is below a coacting relation with the float of the valve mechanism, the valve remains in closed condition to maintain operability of the lift.

This invention relates in general to lifting devices and more particularly to vehicle lifting devices which include a valve mechanism for controlling the egress of pressurized air inserted into the lift mechanism for actuating the latter.

In US. Patent 3,060,900 issued Oct. 30, 1962 to James J. Pelouch, there is disclosed vehicle lifting mechanisms of the general type with which the present invention may be used. Such lifting mechanisms include an air valve assembly including a float member, for controlling the retention of pressurized air applied to the lifting mechanism, and include means for holding the valve of the assembly in seated relationship with the valve seat, to retain the air in the lift mechanism when the operating liquid level is disposed below a predetermined coacting level thereof with the float. However, sometimes, such an arrangement does not hold satisfactorily, and the valve member separates from the valve seat and opens the actuating air to atmosphere before it is desired or proper to lower the lift mechanism.

The present arrangement provides a lifting mechanism including a novel air or gas valve control assembly wherein the valve may be positively locked in seated relationship with the valve seat during raising of the lift, to thereby retain pressurized actuating air of gas in the lift mechanism even when the level of the operating liquid for the lift is disposed below the coacting level of the operating liquid with the float member of the valve mechanism.

Accordingly, an object of the invention is to provide a lifting arrangement including a novel air or gas valve assembly, for controlling the egress of actuating pressurized air or gas from the assembly.

A further object of the invention is to provide a vehicle lift which is adapted to be raised by pressurized air or gas applied to the surface of a liquid in the lift mechanism, and there being provided an air or gas valve assembly for insuring that the level of the liquid in the lift mechanism is at a predetermined proper operating level, with the air valve assembly including a float adapted to lift the valve member into seating engagement with the valve seat of the air valve assembly, when the liquid level in the lift mechanism is at an adequate level, and being adapted to hold the air valve in closed condition during actuation of the lift mechanism by the application of pressurized air or gas to the liquid, to cause actuation of the lift and associated raising of the valve assembly, including the float, with respect to the liquid level, and wherein the air valve mechanism is adapted to open and cause egress of the pressurized air applied to the operating liquid of the lift in the event that the level of liquid is inadequate for proper actuation of the lift.

A still further object of the invention is to provide an air or gas valve mechanism for a lift mechanism for controling egress of pressurized air or gas from the lift mechanism, and which air is applied for actuating the lift mechanism by application of air or gas pressure to liquid in the lift mechanism, and wherein the air valve mechanism comprises a valve seat encompassing an opening extending to the atmosphere for exhausing air from the interior of the lift and a valve member adapted to engage and disengage from said seat with the valve member including an elongated stem with a float operably mounted on the stem for movement relative thereto and adapted to lift the valve member into engagement with the seat when the liquid level in the lift mechanism is adequate for proper actuation of the lift, and which includes shoulder means and coacting seat means adapted for holding the valve member in positive closed condition during actuation of the lift and when the liquid level in the lift is disposed below a coacting level with respect to the float of the valve assembly.

A still further object of the invention is to provide an air valve mechanism for a vehicle lift for controlling the exhausting of pressurized actuating air or gas from the lift, and wherein the valve mechanism comprises a mounting portion defining an opening through which the air is adapted to be passed to atmosphere in the event that the liquid level in the lift is not adequate for proper operation of the lift, and with a bracket member depending from the mounting portion and a valve member including an elongated stern depending from the valve member with a float slidably mounted on the stem, and there being provided an abutment on the stem adapted for engagement with the float upon upward movemen of the float with respect to the stem, to cause lifting of the stern and seating of the valve on the valve sea to close the air exit opening, and thus prevent the egress of air from the lift mechanism, and with the bracket member including a stem guide through which the stern passes during upward and downward movement of the valve and associated stem with respect to the bracket, with such stem guide including a sloping abutment shoulder or lock seat thereon adapted for engagement with a complementary sloping shoulder on the valve stem, for holding thevalve in engaged relation with the valve seat, and with the bracket including a camming portion for swinging the float against the stem upon downward movement of the float with respect to the stem, to cause the shoulder on the stem to engage the lock seat on the stern guide and thus positively hold the valve member in closed relation on the valve seat, even though the level of liquid in the lift is disposed below coacting relation with thefloat of the .valve assembly.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is an elevational, broken sectional view of a lifting mechanism of the semi-hydraulic type, embodying the invention, and showing the lifting mechanism in its lower position;

FIGURE 2 is a sectional elevational view similar to FIGURE 1, with the lift being disposed in a raised position;

FIGURE 3 is an enlarged fragmentary sectional view of the lift mechanism including the air-valve mechanism as attached to the upper end of the piston of the lift mechanism, and illustrating various positions of the float member of the air-valve mechanism;

FIGURE 4 is an enlarged broken, sectional view of the lower part of the air-valve mechanism and showing in particular the coaction between the locking seat on the stem guide member and the complementary shoulder on the valve stem, for holding the valve in closed position when the level of liquid in the lift mechanism relative to the float is disposed below the point where the float would ordinarily hold the valve in closed position;

FIGURE 5 is an enlarged, fragmentary, broken sectional view of the valve and associated stem illustrating the universal attachment or ball and socket joint attachment of the valve to the stem, and also illustrating the shoulder on the lower portion of the stem which is adapted for coaction with the lock seat on the stem guide member of FIGURE 4 in a laterally-urged position of the valve stem;

FIGURE 6 is an enlarged, fragmentary, elevational view of the upper portion of the air valve assembly;

FIGURE 7 is a generally diagrammatic, sectional, elevational view of the air valve assembly as mounted in a full hydraulic type of lift as opposed to the semihydraulic type of lift illustrated in FIGURES 1 through 3.

The lifting mechanism of the present invention is particularly adapted for use as a vehicle lift for lifting vehicles from ground level for the inspection and/or repair thereof.

The lift includes a reciprocal type fluid powered motor unit 10 including a cylinder 12 positioned in a generally vertical position and dsposed below ground level L. A piston 14 is disposed within the cylinder and is adapted for movement between upper and lower positions in the cylinder. FIGURE 1 illustrates the piston of the motor unit in its lowered position, while FIGURE 2 illustrates the position of the motor unit 10 in a raised position, operable to elevate a load, such as a vehicle or the like, above the floor level L.

As can be seen in FIGURES 1 and 2, cylinder 12 may be provided with an inlet conduit 16, having a closure 16a thereon. Conduit 16 is adapted for use in inserting the correct amount of liquid such as hydraulic oil, into the lift. Closure 16:; may include a conventional dip stick 17. As can be seen in FIGURE 2, the bottom wall 18 of the piston may be provided with an opening 20 therethrough, thus communicating the interior of the piston with the interior of the cylinder 12, and providing for entry of the hydraulic liquid into the interior of the piston member 14. A baffle means 22 may be provided coacting with opening 20 for smoothing the flow of the hydraulic liquid through opening 20.

A superstructure 24 may be secured as by means of bolts 26 to the upper end of the piston 14. Such superstructure is adapted to carry mechanism for engaging a vehicle to lift the vehicle from ground level in a manner to provide convenient access to the underside of the vehicle. As can be seen in FIGURES 1 and 2, a safety leg mechanism 30 of generally conventional type, may be secured to the superstructure and which moves with the superstructure and piston. A pivoted latch 32 is provided for coaction with a notch 34 in the safety leg so that once the lift has been raised to its upper position, it

4 cannot be accidentally lowered without disengagement of the latch 32 from the notch 34. The safety leg may be guided during its reciprocal movement with the piston by means of an encompassing guide member 36 recessed into the floor or ground adjacent cylinder 12.

An air or gas conduit 38 is provided, which conduit is adapted for attachment to a suitable source of pressurized air such as a compressor and storage tank (not shown) with conduit 38 extending up through the bottom of the cylinder 12 to substantially the upper end of the cylinder and in generally central, axially-extending relation with respect thereto. A perforated support 40 attached to the interior of the piston may be provided for guiding coaction with the interior portion 38a of the conduit 38, during reciprocal movement of the piston in the cylinder. As can be seen from FIGURE 2, the support 40 is so positioned with respect to the piston so that when the latter is in its uppermost raised position, the guide 40 remains in coacting relation with the air conduit portion 38a.

In accordance with the present invention there is provided an air valve assembly 44 which is adapted to control the egress of the pressurized air passing through the air conduit 38 into the interior of the piston, through the upper end of the piston to the atmosphere. Air valve assembly 44 is preferably easily insertable into the interior of the piston from exteriorly thereof, and in this connection may compirse a threaded head portion 46, defining a passageway 48 therethrough, which passageway at its upper end merges with transversely extending passage or openings 50, thus communicating the interior of the piston 14 with atmosphere. The top plate or wall 54 on the head portion 46 diffuses pressurized air passing through passage 48 and before it emerges from the openings 50. Sealing means 56 may be provided coacting with the head portion 46 for sealing the removable air valve assembly with respect to the threaded sleeve 58 (FIG. 3) secured to the lower cross plate 60 on the upper end of the piston.

The head portion 46 of the valve assembly includes a valve seat 62 on its underside, which valve seat is adapted for coaction with valve member 64 of the air valve assembly for opening and closing passage 48. Valve member 64 may include a somewhat resilient surface 64a thereon, formed for instance from a layer of rubber or plastic material, suitably attached to the valve body, for providing good sealing characteristics between the valve 64 and the valve seat 62. Valve 64 is attached to stem 68 by preferably a universal-type joint attachment 66 which, in the embodiment illustrated, comprises a ball-andsocket connection. A resilient means, such as a compression spring 72, may be provided coacting between the underside of the ball 66a and the inner end of recess 74 in the upper end of the stem, for urging the ball axially outwardly into engagement with the indentation abutment 76 formed in the stem, which indentation coacts with the ball 66a to hold the valve 64 in positive assembled but movable relation with the stern. Adjacent its lower end, the stem is provided with shoulder means 78 which is disposed angularly at an angle X in the embodiment illustrated, of approximately 45 with respect to the horizontal. Shoulder 78 at its lower extremity merges with reduced diameter section 80 of the stem. In the embodiment illustrated, the stem 68 is cylindrical in horizonal cross section, with portion 80 being of approximately one-half the diameter of the upper portion of the stem.

The stem 68 passes through an upper guide 82 comprising an arm with an opening therethrough, through which the stem loosely passes, and at its lower end the stem extends into a lower guide member 84. Lower guide 84 is preferably adjustably mounted in an axial direction on the foot portion 92 of supporting bracket 86 which depends from the head portion 46 of the valve assembly, and, in this connection, guide 84 is exteriorly threaded as at 88, for threaded coaction with an opening 90 extending through the foot portion of bracket 86. Guide 84 may have a gripping portion 94 thereon adapted to be gripped by a wrench or the like, for turning the guide and thus adjusting the axial position of the guide with respect to the foot portion 92 of the bracket 86. A lock nut 96 coacting in threaded relation with the threaded portion 88 of guide 84 may be provided for locking guide 84 in predetermined axially oriented position with respect to bracket 86. .As can be seen from FIG. 4, the guide 84 defines a passageway 98 preferably extending completely therethrough, with the upper end of passageway 98 being beveled as at 100, to provide an oblique lock seat arrangement adapted for abutting supporting coaction with shoulder 78 on the stem 68, for holding the valve in closed condition against seat 62 for lifting operation on the piston 12 of the lift mechanism. Shoulder 78 is maintained in abutting coaction with lock seat 100 by the lateral urging of the stem 68 due to the coaction between the float member 102 on the valve stem and cam portion 106 of bracket 86, as will be hereinafter described in greater detail.

The float member 102 is preferably of hollow construction and includes a channel-way 108 (FIGS. 3 and 4) therethrough so that the float member can readily move axially with respect to the valve stem 68. An abutment 110 in the form (in the embodiment illustrated) of a wire twisted about the stem -68 in gripping relation, may be provided for limiting the upward movement of the float member 102 relative to stem 68. The downward movement of float 102 is limited by the engagement of the float with the aforementioned diagonally arranged cam surface 106 on bracket 86.

Operation of the lift mechanism may be as follows: When it is desired to elevate the lift and thus raise the piston from the floor level, pressurized air is inserted into the hollow upper end of the piston 14 via the air conduit 38. If the liquid level in the lift is adequate, the valve member 64 will be seated against the valve seat 62, and thus prevent the egress of such pressurized air through exit opening 48 in the valve assembly. It will be seen that an adequate level of liquid causes the float 102 to move upwardly relative to the stem 68 until it engages abutment 110 on the stem, and will then lift the stem and associated valve 64 upwardly to cause sealing engagement between the valve 64 and the valve seat 62. The aforementioned universal joint connection 66 of the valve to the stern and the spring loaded axial movement of the valve, together with the resilient surface 64a thereof, insures a good sealing relation between the valve 64 and the valve seat 62.

Now if it so happens that the level of liquid in the lift is not adequate to cause the float 102 to move upwardly relative to the stem and engage the abuptment 110 and then sufliciently lift the stern associated with valve 64 for sealing engagement of the latter with the valve seat 62, then opening 48 will permit egress of pressurized air applied through air conduit 38 to the interior of the piston, with such air flowing outwardly through openings 50 and above the uppermost end plate 114 of the piston and out slot means 116 in the superstructure 24. Accordingly, the escaping of the pressurized air from the interior of the piston will indicate to the operator of the lift that the liquid level is too low to cause closure of the air valve assembly, and will indicate to him that more liquid has to be added via the liquid inlet pipe 16.

Assuming that there is adequate liquid in the lift mechanism and that the float 102 has moved the valve 64 into seating engagement with valve seat -62, then the pressurized air applied via the air conduit 38 will operate to apply air pressure to the piston and move it upwardly to an elevated position. During this upward movement of the piston 14 and valve assembly 44 with respect to the liquid in the lift, the float 102 will, of course, move downwardly relative to the valve stem when the liquid no longer coacts with the float to maintain it in contact with the abutment 110 of the stem. However, the air pressure acting on the underside of the valve 64 during the upward movement of the piston will maintain the valve in closed condition. As the float 102 moves downwardly relative to the stem 68, the float engages the cam section 106 on bracket 86 causingthe stem to be shifted laterally away from olfset portion 118 of bracket 86, and causes movement of the shoulder 78 on the valve stem into abutting coaction with the lock seat 100 on the stem guide 84. The engaged position of the float 102 with the cam portion 106 on bracket '86 is shownin dot-dash lines in FIGURE 3, and as shown in FIGURE 4, the float engaging the stern moves it laterally to hold the shoulder 78 on the stern in position on lock seat 100 on guide 84. Accordingly, the valve 64 is positively maintained in closed position during elevation of the piston to the position illustrated, for instance, in FIGURE 2. In the latter position, latch 32 coacting with slot 34 in the safety leg, maintains the latter in activated condition.

When it is desired to lower the lift mechanism, a valve mechanism (not shown) connected to pressurized air conduit 38 may be opened permitting the pressurized air to escape via the conduit 38, and thus releasing the pressure and permitting the piston to move downwardly to be retracted back into the cylinder 14. As'the latter happens, the liquid level will engage the float 102 and move it upwardly relative to the stem out of coacting relationship with the cam portion 106. When the latter happens, the valve stem, due to the sloping coaction of shoulder 78 on the stem and seat 100 on the guide will permit the stem to move back into a generally centered condition with respect to the opening 98 through the guide 84. The latter described hydraulic lift is one known in the art as a semihydraulic lift.

It will be understood that if the pressurized air in piston 14 is inadvertently released via air conduit 38 without releasing the latch 32 on the safety leg 30, the piston cannot lower, and even though the valve 64 would no longer be held in closed position by air pressure in the piston, the engagement of the shoulder on stem 68 with seat 100 as maintained by the laterally cammed float 102 will hold valve 64 in closed condition. Thereafter pressurized air can once again be inserted via conduit 38 into the piston (valve 64 remaining closed) and the latch 32 can be disengaged, and then the air exhausted via conduit 38 to permit lowering of the lift.

Referring now to FIGURE 7, there is shown what i known in the art as a full hydraulic lift, with such full hydraulic lift mechanism embodying an air valve assembly 44 of the same readily removable type as that aforedescribed in connection with the semi-hydraulic lift. Such full hydraulic lift may include a cylinder 120 located 'below floor level L and in a generally vertical position. A piston 122 is positioned in the cylinder and adapted to be raised and lowered from the full line position illustrated in FIG. 7 to the dot-dash position illustrated therein. A sealing or packing means 124 may be provided coacting between the piston and the cylinder for sealing the hydraulic fluid disposed in the cylinder 120. A vehicleengaging superstructure 126 may be secured to the piston in a generally similar manner as aforedescribed and by any appropriate means, and a safety leg 130 and associated latch 131 may be provided in a similar manner as aforedescribed in connection with the first embodiment.

A hydraulic fluid supply tank 132 is provided with such supply tank in the embodiment illustrated shown as being positioned above ground level. A hydraulic conduit 134 leads from the supply tank to an inlet port 136 in the cylinder for supplying hydraulic liquid to the cylinder to cause upward movement of the piston 122. A valve 138 may be provided in'supply line 134 for permitting the liquid to pass from the supply tank to the cylinder, but restricting the return flow of liquid unless valve 138 is actuated by the lift operator. An air supply conduit 140 with a control valve 142 disposed therein is provided for supplying pressurized air to the supply tank. Line 140 .enters the supply tank at the upper end thereof and there may be provided a baflle plate 144 for diffusing the air as it enters the tank. When pressurized air is applied to the supply tank via line 140, the hydraulic liquid is forced up supply pipe portion 134 to the cylinder 120, thus causing raising of the piston 122 to an elevated condition. This is assuming, of course, that the supply of liquid in the tank is adequate for causing closing of the valve member 64 of the valve assembly 44, or in other words, with the liquid level being suflicient to cause the float to engage the abutment 110 on the stem 68 and move the valve 64 into sealing engagement with the associated valve seat 62. However, if the level of the liquid is not adequate, then the float 102 has moved downwardly thus permitting the stem and associated valve 64 to move downwardly away from the valve seat 62, opening the supply tank to atmosphere. Accordingly, if pressurized air is applied to the supply tank, the pressurized air will exit through the exit opening 48 in the valve assembly and will fail to actuate the lift, thus indicating to the operator that the supply of hydraulic fluid in the tank is not adequate for proper operation of the lift.

During actuation of the lift, the level of the hydraulic fluid will fall below coaction with the float and a positive locking of the valve member in closed position occurs due to the lateral swinging of the valve stem by the float coacting with the cam portion 106, thus causing abutting holding coaction between the shoulder 78 on the valve stem and the lock seat 100 on the stem guide 84.

When it is desired to lower the lift, the safety leg 130 may be deactivated and the valve 142 is actuated thereby permitting the pressurized air in the supply tank to exhaust via valve 142 to atmosphere, and permitting the liquid to be returned to the supply tank by gravity or downward movement of the piston and associated superstructure, thus forcing the hydraulic liquid back through line 134 into the supply tank.

If, through inadvertence, the safety leg has not been disengaged and the pressurized air has been released from the supply tank via the valve 142, there will be no pressurized air acting on the valve 64 of the air valve assembly and thus under normal circumstances such valve assembly would move away from the valve seat. However, due to the camming coaction of cam portion 106 with the float 102 urging the valve stem 68 laterally so that holding or locking engagement occurs between shoulder 78 on the stern and seat 100 on the guide member 84, the valve member 64 remains in closed condition with respect to the valve seat. Thereafter, pressurized air can be again reinserted into the supply tank and then the safety leg can be deactivated and then the lift lowered.

From the foregoing description and accompanying drawings, it will be seen that the invention provides a lifting mechanism including a novel air valve control assembly which is readily insertable into the lift from exteriorly of the lifting mechanism, for convenient replacement and/or repair thereof, and which valve member of the valve assembly may be positively locked in seated relation with the valve seat for retaining pressurized actuating air in the lift mechanism after the level of the operating liquid for the lift has dropped below the coacting level of the operating liquid with an associated float member of the air valve assembly.

The invention also provides an air valve assembly having a valve member which is resiliently and universally connected to a valve stem, which valve stem includes shoulder means adapted for abutting coaction with seat means on an adjustable stern guide member, with the stem being adapted for lateral movement so that the shoulder means engages the seat means in abutting relation when the float member coacting with the stem engages in coacting relation with a cam portion during downwardly movement of the float with respect to the stem.

What is claimed is:

1. In lifting mechanism comprising in combination, a generally vertically oriented fluid powered reciprocal type motor unit including a cylinder-like member and a piston-like member coacting with said cylinder-like member, said mechanism being adapted to contain hydraulic liquid, means for inserting pressurized air into said mechanism for moving one of said members axially with respect to the other of said members, an air valve assembly on said mechanism operative for controlling the retention of pressurized air in said mechanism, said assembly including movable float means adapted for coaction with the hydraulic liquid for operating said assembly, and adapted to automatically open said assembly when the hydraulic liquid in said mechanism is below a predetermined level, and shoulder means on said assembly adapted for actuation by said float means to hold said valve assembly in closed condition upon predetermined movement of said float means.

2. A mechanism in accordance with claim 1 wherein said air valve assembly comprises a movable valve member, a valve seat with which said valve member is adapted for coaction to place said assembly in closed condition, said float means coacting with said valve member to move the latter into coaction with said valve seat when the level of hydraulic liquid in said mechanism is at an adequate level, and seat means on said assembly adapted for coaction with said shoulder means for holding said valve member in engaged relation with said valve seat upon actuation of said shoulder means by said float means.

3. A mechanism in accordance with claim 2 wherein said valve member comprises a valve head and a stem depending from said valve head, an abutment on said stem and said float means being disposed on said stem and being movable axially with respect to said stem, and being adapted for engagement with said abutment for lifting said valve head into sealing engagement with said valve seat, said shoulder means being disposed on said stem, and means disposed below said float means and adapted for engagement with said float means to move said stem laterally to cause said engagement of said shouder means with said seat means on said assembly.

4. A mechanism in accordance with claim 3 including means movably connecting said valve head to said stem.

5. A mechanism in accordanw with claim 4 wherein the last mentioned means comprises a ball and socket joint connection, and resilient means coacting between said connection and the stem for resiliently and movably mounting the valve head on said stem.

6. A mechanism in accordance with claim 3 wherein said stem is of cylindrical configuration in cross section and includes a section of reduced diameter, said reduced diameter section providing an oblique surface adjacent thereto forming said shoulder means.

7. A mechanism in accordance with claim 3 including a guide on said assembly for guiding the axial movement of said stem during opening and closing movements of said valve member, and wherein said guide includes a threaded axially apertured thimble for adjusting the axial position thereof with respect to said valve seat, said seat means being disposed on said thimble for movement therewith, and means for locking said thimble in predetermined axial position with respect to said valve seat.

8. A mechanism in accordance with claim 3 wherein said shoulder means is formed by an oblique surface on said stem, said surface being oriented so as to extend at an angle of approximately 45 with respect to the horizontal.

9. A mechanism in accordance with claim 3 wherein said assembly includes a mounting head portion removably attached to said mechanism and locating said stem, valve head and float means internally of said mechanism, a bracket depending from said mounting head portion and extending alongside said stem, said bracket including a portion guiding said stem during the latters axial movement, said means which is disposed below said float means comprising a cam on said bracket extending inwardly toward said stem and adapted for engagement with said float means for causing said float means to urge said stem laterally with respect to said bracket whereby said shoulder means on said stem will engage said seat means.

10. A mechanism in accordance with claim 3 wherein said assembly includes a mounting head portion threaded on the exterior thereof and adapted for threaded coaction with a threaded opening in the lifting mechanism, for ready insertion of said air valve assembly into said lifting mechanism from exteriorly of said lifting mechanism.

11. A mechanism in accordance with claim wherein said mounting head portion includes openings therein providing lateral passageway means for egress of pressurized air from said lifting mechanism.

12. In an air valve assembly adapted for mounting in a fluid actuated vehicle lift mechanism of the type embodying hydraulic liquid, for controlling the retention of pressurized air in the mechanism, said assembly comprising a mounting head portion, means for attaching the head portion to the lift mechanism from exteriorly of the lift mechanism so that the valve assembly can be readily removed from and reinserted back into said lift mechanism, a valve seat, a movable valve member including a stem depending therefrom, a movable float member coacting with said stern in relative axially movable relation, said float member adapted to coact with the hydraulic liquid in the lift for operating said valve assembly, and adapted to automatically open said valve member when the hydraulic liquid is below a predetermined level, and means including shoulder means on said stem adapted for actuation by said float member into engaged coaction with seat means on said assembly for holding said valve member in closed condition against said valve seat upon predetermined movement of said float member.

13. An air valve assembly in accordance with claim 12 including means movably connecting said valve member to said stem.

14. An air valve assembly in accordance with claim 13 wherein the last mentioned means comprises a ball and socket joint connection, and resilient means coacting between said connection and the stem for resiliently and movably mounting the valve member on said stem.

15. An air valve assembly in accordance with claim 12 wherein said stem is of cylindrical configuration in cross section and includes a section of reduced diameter, said reduced diameter section including an oblique shoulder adjacent thereto forming said shoulder means which is adapted for engaged coaction with said seat means on said assembly.

16. An air valve assembly in accordance with claim 12 wherein said seat means includes an apertured guide receiving said stem therein, said guide including means for adjusting the axial position of the guide with respect to said valve seat and thus providing for adjusting the position of said seat means with respect to said valve seat.

17. An air valve assembly in accordance with claim 15 wherein said shoulder is oriented so as to extend at an angle of approximately 45 with respect to the horizontal.

18. An air valve assembly in accordance with claim 12 including a bracket depending from said mounting head portion and extending alongside said stem, cam means on said bracket extending inwardly toward said stern and adapted for engagement with said float member for causing said float member to coact with said stern and urge the latter laterally away from said bracket whereby said shoulder means on said stem will engage said seat means.

19. An air valve assembly in accordance with claim 12 wherein said stem includes an abutment thereon adapted for engagement with said float member for causing upward movement of said stern and associated valve member upon upward movement of the float member.

20. An air valve assembly in accordance with claim 18 wherein said bracket includes an arm extending outwardly therefrom and having an opening therethrough through which said stern passes, said bracket also including a foot portion extending generally horizontally therefrom and having threaded means thereon, said seat means including an apertured, exteriorly threaded guide receiving said stem therein, said guide coacting with said threaded means for adjustably mounting said guide, said cam means being disposed above said foot portion.

References Cited UNITED STATES PATENTS 2,550,882 5/1951 Sturm et al 91-4 2,637,302 5/ 1953 Harrison et al 9l--4 3,060,900 10/ 1962 Pelouch 91-4 3,179,014 4/1965 Hoff et a]. 9l--4 PAUL E. MASLOUSKY, Primary Examiner US. Cl. X.R. -545; 9281 

